Toaster using infrared heating for reduced toasting time

ABSTRACT

A toaster uses radiant heat at infrared wavelengths optimized for producing rapid and uniform toasting of a food product. The infrared wavelengths of the radiated heat are selected for optimum speed and quality (browning and moisture content) of the food product. The selected infrared wavelengths of the radiated heat may also effectively defrost a food product. Defrosting of the food product by the infrared radiated heat adds very little time in obtaining a desired toast color to the food product. A plurality of infrared wavelengths of radiated heat may also be used, wherein the plurality of infrared wavelengths are selected for optimal heat penetration and surface browning of the food product. Shorter wavelengths for browning and slightly longer wavelengths to penetrate the food product for evaporating the moisture therein to allow surface browning by the shorter wavelengths. In addition, the heating energy within the toaster may be further elongated (longer wavelengths) once the infrared radiation is re-radiated off of reflectors within the toaster. The wavelengths of infrared radiated heat may be from about 1 to about 3 microns, and preferably from about 1.96 to about 2.5 microns, and most preferably at about 2.11 microns.

BACKGROUND OF THE INVENTION TECHNOLOGY

1. Field of the Invention

The present invention relates to electric toasters, and morespecifically, to an infrared heated electric toaster having reducedtoasting time and improved browning consistency.

2. Background of the Related Technology

Toasting of food products, e.g., breads and pastries, requires thatmoisture be removed therefrom so that the surface of the food productwill turn brown upon further application of heat thereto. This hasgenerally required several minutes of time for a food product that isrelatively fresh (high moisture content). Over the years there -havebeen many attempts at finding ways to speed up toasting of foodproducts. Toaster appliances employing various technologies, e.g.,calrods, mica card heating elements, halogen high intensity light, and,in addition, higher power heating elements have been used, however, allhave fallen short of consumer's expectations. With the toasterappliances used in the past, there were usually some tradeoffs made bythe consumer in order to gain faster toasting speed. Consumers mightcomprise toasting quality, safety, etc., in favor of speed.

Therefore, a problem exists, and a solution is required for improvingthe speed and quality of toasting food products.

SUMMARY OF THE INVENTION

The present invention remedies the shortcomings of present toastingtechnologies by providing a toaster using radiant heat at infraredwavelengths optimized for producing rapid and uniform toasting of a foodproduct. The infrared wavelengths of the radiated heat are selected foroptimum speed and quality (browning and moisture content) of the foodproduct. The selected infrared wavelengths of the radiated heat may alsoeffectively defrost a food product. Defrosting of the food product bythe infrared radiated heat adds very little time in obtaining a desiredtoast color to the food product. A typical food product toasting timefor the present invention may be about one minute.

The invention may emit a plurality of infrared wavelengths of radiatedheat, wherein the plurality of infrared wavelengths are selected foroptimal heat penetration and surface browning of the food product, e.g.,shorter wavelengths for browning and slightly longer wavelengths topenetrate the food product for evaporating the moisture therein to allowsurface browning by the shorter wavelengths. In addition, the heatingenergy within the toaster may be further elongated (longer wavelengths)once the infrared radiation is re-radiated off of reflectors within thetoaster. The wavelengths of infrared radiated heat may be from about 1to about 3 microns, and preferably from about 1.96 to about 2.5 microns,and most preferably at about 2.11 microns.

According to exemplary embodiments of the invention, the infraredwavelength radiation emitting heaters may be cylindrical and maycomprise any type of material that can be used for resistance heatingand is capable of emitting heating energy at infrared wavelengths, e.g.,metal alloy filament materials such as, for example but not limited to,Ni Fe, Ni Cr, Ni Cr Fe and Fe Cr Al, where the symbols: Ni representsnickel, Fe represents iron, Cr represents chromium, and Al representsaluminum. The infrared wavelength emitting filament material may eitherbe exposed or preferably enclosed within a high temperature infraredwavelength transparent tube, such as for example, a high temperaturequartz tube, e.g., 99.9 percent pure quartz (SiO₂), and may be clear,chemically etched, or have extruded grooves therein depending upon thedesired infrared wavelength(s) to be emitted. The filament material maybe heated by an electric current, alternating or direct, to atemperature sufficient for the emission of energy at a desired infraredwavelength(s). The infrared wavelength(s) emitted from the heater may bechanged by changing the voltage applied to the filament material.

Some of the infrared wavelength energy may be directed toward thesurface of the food product from heat reflectors located about orproximate, e.g., the infrared wavelength energy emitter (source) islocated between the heat reflector and the food product being toasted.The heat reflectors may be designed so as to evenly distribute theinfrared wavelength energy over the surface of the food product forconsistent browning thereof. The emitted infrared wavelengths that areradiated directly onto the surface of the food product may be selectedfor optimal browning of the food product, and the infrared wavelengthenergy reflected by the heat reflectors may be at longer infraredwavelengths than the directly radiated infrared wavelength energy. Thelonger infrared wavelength energy will penetrate deeper into the foodproduct to aid in removing moisture therefrom before surface browningoccurs. The heat reflectors may be fabricated from aluminized steel,bright chrome plated metal and the like.

A gold coating, which is a very efficient reflector of infraredwavelengths, may also be placed over a portion of the quartz tube of theheater. This gold coating may be used to direct infrared wavelengthenergy as desired, e.g., toward the surface of the food product, andreduce the amount of infrared wavelength energy from the side of thequartz tube opposite the surface of the food product. Thus the goldcoating will substantially reduce the infrared wavelength radiation indirections that are not useful for heating and browning of the foodproduct. In addition, the gold coating helps reduce the temperature ofsurfaces behind the gold coating. By reducing infrared wavelength energyfrom surfaces not useful for toasting, e.g., facing toaster housingsurfaces, the metallic housing of a toaster product may be cool to thetouch. The gold coating may be of any thickness, preferably about onemicron in thickness.

According to an exemplary embodiment of the invention, a toastercomprises a toasting chamber adapted to receive a food product, e.g.,bread, pastries, bagels, English muffins, biscuits, waffles, etc.,infrared wavelength emitting radiant heat sources located on either sideof the toasting chamber, and heat reflectors proximate or adjacent tothe infrared wavelength heat sources, the infrared wavelength heatsources advantageously being located between the toasting chamber andthe reflectors. The toaster may have an ejector mechanism located at thebottom of the food product toasting chamber, the ejector adapted toexpel the food product from the toasting chamber when toasting thereofis complete. An enclosure surrounds the food product toasting chamber,infrared wavelength heat sources and heat reflectors. Controls for thetoaster may also be attached to the enclosure, and/or be an integralpart thereof. The food product toasting chamber may be adapted toreceive one or more items of the food product, e.g., slice(s) of bread.

It is contemplated and within the scope of the present invention thatmore than one food product toasting chamber may be provided in atoaster. Each of the toasting chambers may advantageously beindependently controllable, e.g., different toasting settings for eachchamber. Each of the more than one food product toasting chambers mayhave associated infrared wavelength heat sources on either side of therespective toasting chamber, and heat reflectors may be adjacent to eachof these infrared wavelength heat sources, the infrared wavelength heatsources being located between the respective toasting chamber and therespective reflectors. It is also contemplated and within the scope ofthe invention that longer wavelength infrared radiant energy emittingheat sources and/or from the heat reflectors may be used to improve therate of moisture evaporation of the food product so as to allow evenfaster surface browning thereof.

A technical advantage of the present invention is faster toasting offood products. Another technical advantage is more even browning oftoasted food products. Still another technical advantage is faster andmore even toasting of a variety of food products, e.g., different typesof breads and pastries. Yet another advantage is good toast colorshading on the surface while retaining a substantial portion of themoisture content of the food product. Still another technical advantageis defrosting and toasting of frozen food products. Still anothertechnical advantage is uniform toast shades over non-uniform width foodproducts. Yet another advantage is using longer infrared wavelengths incombination with the selected browning infrared wavelengths forimproving the rate of moisture evaporation of the food product so as toallow even faster surface browning thereof. Other technical advantagesshould be apparent to one of ordinary skill in the art in view of whathas been disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present disclosure and advantagesthereof may be acquired by referring to the following description takenin conjunction with the accompanying drawings wherein:

FIG. 1 is a schematic elevational view of a cutaway section of aninfrared toaster, according to an exemplary embodiment of the presentinvention;

FIG. 2 is a schematic top view of the infrared toaster illustrated inFIG. 1;

FIG. 3 is a schematic top view of an infrared toaster having greatercapacity, according to another exemplary embodiment of the presentinvention;

FIG. 4 is a schematic top view of an infrared toaster having evengreater capacity, according to yet another exemplary embodiment of thepresent invention; and

FIG. 5 is a schematic elevational view of the front controls of theinfrared toaster, according to the exemplary embodiments of the presentinvention.

The present invention may be susceptible to various modifications andalternative forms. Specific exemplary embodiments thereof are shown byway of example in the drawing and are described herein in detail. Itshould be understood, however, that the description set forth herein ofspecific embodiments is not intended to limit the present invention tothe particular forms disclosed. Rather, all modifications, alternatives,and equivalents falling within the spirit and scope of the invention asdefined by the appended claims are intended to be covered.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Referring now to the drawings, the details of exemplary embodiments ofthe present invention are schematically illustrated. Like elements inthe drawings will be represented by like numbers, and similar elementswill be represented by like numbers with a different lower case lettersuffix.

Referring now to FIG. 1, depicted is a schematic elevational view of acutaway section of an infrared toaster, according to an exemplaryembodiment of the present invention. The infrared toaster, generallyrepresented by the numeral 100, comprises infrared wavelength emittingradiant heat sources (hereinafter IR heaters) 102 and 104, radiant heatreflectors 106 and 108, a toasting chamber 110 for a food product (notshown), food product centering guides 112, a food product ejector 114,and a toaster housing 116. The centering guides 112 may be outwardlybiased with springs 118. The centering guides 112 may be wires and thelike. The ejector 114 is adapted, in a first position, to support thefood product (not shown) inside the toasting chamber 110 during toastingthereof, and to eject (push up), in a second position, the toasted foodproduct from the toasting chamber 110.

The IR heaters 102 and 104 are positioned so as to emit infrared radiantheat directly onto the surface of the food product located in thetoasting chamber 110. The reflectors 106 and 108 are shaped so as toreflect onto the food product in the toasting chamber 110, infraredradiant heat from the IR heaters 102 and 104. It is contemplated andwithin the scope of the invention that the IR heaters 102 and 104 mayhave any shape or form that advantageously directs infrared radiant heatinto the food product in an even and uniform manner. The infraredradiant heat reflected-from the reflectors 106 and 108 may be at alonger wavelength than the directly emitted infrared radiant heat fromthe IR heaters 102 and 104. This longer wavelength infrared radiant heatpenetrates deeper into the food, thus shortening the moistureevaporation time of the food product before surface browning may occur.The wavelengths of infrared radiated heat may be from about 1 to about 3microns, and preferably from about 1.96 to about 2.5 microns, and mostpreferably at about 2.11 microns.

The IR heaters 102 and 104 may be a filament 124 whereby electricalcurrent is passed through the filament so as to heat the filament to atemperature at which a desired wavelength of infrared energy is radiatedtherefrom. The IR heaters 102 and 104 may radiate a plurality ofwavelengths of infrared energy as well as wavelengths of visible light.Material for and electrical current through the IR heaters 102 and 104are selected so that the heaters produce predominantly the desiredinfrared wavelength or wavelengths for toasting of the food product. Thefilaments 124 of the IR heaters 102 and 104 may be comprised of any typeof material that can be used for resistance heating and is capable ofemitting heating energy at infrared wavelengths, e.g., metal alloyfilament materials such as, for example but not limited to, Ni Fe, NiCr, Ni Cr Fe and Fe Cr Al, where the symbols: Ni represents nickel, Ferepresents iron, Cr represents chromium, and Al represents aluminum. Thefilament 124 may either be exposed or preferably enclosed within a hightemperature infrared wavelength transparent tube, such as for example, ahigh temperature quartz tube 126. The quartz tube 126 may be clear,chemically etched, or have extruded grooves therein depending upon thedesired infrared wavelength to be emitted therethrough. Electricalcurrent through each filament 124 of the IR heaters 102 and 104 maypreferably be about five amperes at about 120 volts, resulting in apower draw for each of the IR heaters 102 and 104 of about 600 watts.Thus, the toaster 100 may use a total of about 1200 watts of power whichis well within the rating of a standard 15 or 20 ampere, 120 volt wallreceptacle in a home or business, e.g., kitchen receptacle. It iscontemplated and within the scope of the present invention that otheroperating voltages and currents may be used so long as the desiredinfrared wavelength(s) of radiant heat energy is produced.

The housing 116 may be metal and/or plastic. The housing 116 is openabove the toasting chamber 110 so that the food product may be insertedinto the toasting chamber 110 in a direction 120. Toasting controls 502(see FIG. 5) for the toaster 100 may be located on the housing 116. Agold coating 122 may be applied to the quartz glass tubes 126 forreflecting the infrared wavelength energy away from the portions of thequartz glass tubes 126 that do not substantially contribute to theradiant heating and browning of the food product. The gold coating 122will help in reducing the surface temperature of the housing 116. Inaddition, an air space between the housing 116 and the reflectors 106and 108 also aid in reducing the surface temperature of the housing 116during toasting of the food product.

Referring now to FIG. 2, depicted is a schematic top view of theinfrared toaster illustrated in FIG. 1. The food product 230 is locatedin the toasting chamber 110. More than one piece of the food product 230may be placed into the toasting chamber 110, depending upon the sizethereof.

Referring now to FIG. 3, depicted is a schematic top view of an infraredtoaster having greater capacity, according to another exemplaryembodiment of the present invention. The toaster 100 a has at least twotoasting chambers 310 a and 310 b into which food products 230 a and 230b may be inserted, respectively. Either a single pair of IR heaters(e.g., 102 and 104 of FIG. 1) may be positioned on either side of thefood products 230 a and 230 b, or individual pairs of IR heaters andreflectors may be used for each of the two toasting chambers 310 a and310 b.

Referring now to FIG. 4, depicted is a schematic top view of an infraredtoaster having even greater capacity, according to yet another exemplaryembodiment of the present invention. The toaster 100 b has at least twotoasting chambers 410 a and 410 b into which a plurality of foodproducts 230 a-230 b and 230 c-230 d may be inserted, respectively.Either a single pair of IR heaters (e.g., 102 and 104 of FIG. 1) foreach of the toasting chambers 410 a and 410 b may be positioned oneither side of the food products 230 a-230 b and 230 c-230 d,respectively, or individual pairs of IR heaters and reflectors may beused for each of the plurality of food products 230 a-230 c.

Referring now to FIG. 5, depicted is a schematic elevational view of thefront controls of the infrared toaster, according to the exemplaryembodiments of the present invention. A control panel 540 may be locatedanywhere on the housing 116 so long as the controls of the panel 540 areeasy to use. The controls of the panel 540 may be used to set thedesired toast color and the like. Also contemplated may be a control forcausing the ejector 114 to manually ejecting the food product 230 fromthe toasting chamber 110.

The invention, therefore, is well adapted to carry out the objects andto attain the ends and advantages mentioned, as well as others inherenttherein. While the invention has been depicted, described, and isdefined by reference to exemplary embodiments of the invention, suchreferences do not imply a limitation on the invention, and no suchlimitation is to be inferred. The invention is capable of considerablemodification, alteration, and equivalents in form and function, as willoccur to those ordinarily skilled in the pertinent arts and having thebenefit of this disclosure. The depicted and described embodiments ofthe invention are exemplary only, and are not exhaustive-of the scope ofthe invention. Consequently, the invention is intended to be limitedonly by the spirit and scope of the appended claims, giving fullcognizance to equivalents in all respects.

1. An apparatus for toasting a food product, comprising: a toastingchamber adapted for receiving a food product to be toasted, the toastingchamber having first and second sides; a first infrared heater locatedon the first side of the toasting chamber; a second infrared heaterlocated on the second side of the toasting chamber; a first radiant heatreflector located on the first side of the toasting chamber, wherein thefirst infrared heater is located between the toasting chamber and thefirst radiant heat reflector; and a second radiant heat reflectorlocated on the second side of the toasting chamber, wherein the secondinfrared heater is located between the toasting chamber and the secondradiant heat reflector; wherein the first and second infrared heatersemit infrared radiant heat at a wavelength optimized for toasting of thefood product.
 2. The apparatus of claim 1, wherein the toasting chamberhas centering guides for positioning the food product between the firstand second infrared heaters.
 3. The apparatus of claim 2, wherein thecentering guides are comprised of wires forming the first and secondsides of the toasting chamber.
 4. The apparatus of claim 2, wherein thecentering guides are outwardly biased.
 5. The apparatus of claim 1,wherein the first and second infrared heaters are electricallyconductive filaments adapted to pass a desired amount of electriccurrent therethrough.
 6. The apparatus of claim 5, wherein theelectrically conductive filaments are a composition of nickel (Ni) andiron (Fe).
 7. The apparatus of claim 5, wherein the electricallyconductive filaments are comprised of a composition of nickel (Ni) andchromium (Cr).
 8. The apparatus of claim 5, wherein the electricallyconductive filaments are comprised of a composition of nickel (Ni),chromium (Cr) and iron (Fe).
 9. The apparatus of claim 5, wherein theelectrically conductive filaments are comprised of a composition of iron(Fe), chromium (Cr) and aluminum (Al).
 10. The apparatus of claim 1,wherein each of the first and second infrared heaters comprise anelectrically conductive filament inside of a quartz glass tube.
 11. Theapparatus of claim 10, wherein the quartz glass tube is clear.
 12. Theapparatus of claim 10, wherein the quartz glass tube is chemicallyetched so as to pass a desired infrared wavelength from the electricallyconductive filament.
 13. The apparatus of claim 10, wherein the quartzglass tube has extruded grooves therein so as to pass a desired infraredwavelength from the electrically conductive filament.
 14. The apparatusof claim 1, wherein the first and second radiant heat reflectors reflectradiant heat from the first and second infrared heaters onto the foodproduct surfaces facing the first and second sides, respectively, of thetoasting chamber.
 15. The apparatus of claim 14, wherein the first andsecond radiant heat reflectors are optimized to evenly distributeradiant heat onto surfaces of the food product.
 16. The apparatus ofclaim 1, wherein the infrared wavelength is from about 1 to about 3microns.
 17. The apparatus of claim 1, wherein the infrared wavelengthis from about 1.96 to about 2.5 microns.
 18. The apparatus of claim 1,wherein the infrared wavelength is about 2.11 microns.
 19. The apparatusof claim 1, wherein the infrared wavelength comprises a plurality ofinfrared wavelengths optimized for toasting of the food product.
 20. Theapparatus of claim 14, wherein the reflected radiant heat is at a longerinfrared wavelength than the infrared wavelength of the radiant heatfrom the first and second infrared heaters.
 21. The apparatus of claim10, further comprising a gold coating over a portion of the quartz glasstube, wherein the gold coated portion is on the distal side of thequartz glass tube from the food product.
 22. The apparatus of claim 1,further comprising a food product ejector having a first position and asecond position, wherein when in the first position the food product ispositioned inside the toasting chamber and when in the second positionthe food product is ejected from the toasting chamber.
 23. The apparatusof claim 1, further comprising a housing, wherein the housing enclosesthe toasting chamber, the first and second infrared heaters, and thefirst and second radiant heater reflectors.
 24. The apparatus of claim23, further comprising toasting controls located on the housing.
 25. Anapparatus for toasting a food product, comprising: a plurality oftoasting chambers, each of the plurality of toasting chambers having afirst side and a second side and each of the plurality of toastingchambers is adapted for receiving a food product to be toasted; a firstinfrared heater for plurality of toasting chambers and located on thefirst side thereof; a second infrared heater for the plurality oftoasting chambers and located on the second side thereof; a firstradiant heat reflector located on the first side of the plurality oftoasting chambers, wherein the first infrared heater is located betweenthe plurality of toasting chambers and the first radiant heat reflector;and a second radiant heat reflector located on the second side of theplurality of toasting chambers, wherein the second infrared heater islocated between the plurality of toasting chambers and the secondradiant heat reflector; wherein the first and second infrared heatersemit infrared wavelength radiant heat at a wavelength optimized fortoasting of the food product in each of the plurality of toastingchambers.
 26. The apparatus of claim 25, further comprising first andsecond infrared heaters for each of the plurality of toasting chambers.27. The apparatus of claim 25, further comprising first and secondradiant heat reflectors for each of the plurality of toasting chambers.28. A method for toasting a food product with infrared radiant heat,said method comprising the steps of: evaporating moisture from andbrowning surfaces of a food product in a toasting chamber with radiantheat at a first infrared wavelength emitted from infrared heaterslocated on each side of the food product and radiant heat at a secondinfrared wavelength reflected from radiant heat reflectors located oneach side of the food product wherein the infrared heaters are locatedbetween the radiant heat reflectors and the food product.
 29. The methodof claim 28, wherein the second infrared wavelength is longer than thefirst infrared wavelength.
 30. The method of claim 29, wherein theradiant heat at the second infrared wavelength penetrates deeper intothe food product than the radiant heat at the first infrared wavelength.31. The method of claim 29, wherein the radiant heat at the secondinfrared wavelength evaporates the moisture from the food product fastthan the radiant heat at the first infrared wavelength.
 32. The methodof claim 29, wherein the radiant heat at the first infrared wavelengthbrowns the food product surface.
 33. The method of claim 28, furthercomprising the step of defrosting the food product with the radiantheat.
 34. The method of claim 28, wherein radiant heat at the first andsecond infrared wavelengths are reflected from the radiant heatreflectors onto the food product.
 35. The method of claim 28, furtherproviding the step of emitting radiant heat from the infrared heatersonto the food product at a first plurality of infrared wavelengths. 36.The method of claim 28, further providing the step of reflecting radiantheat from the radiant heat reflectors onto the food product at a secondplurality of infrared wavelengths.
 37. The method of claim 28, whereinthe first infrared wavelength is selected for substantially optimumbrowning of the food product.
 38. The method of claim 28, wherein thesecond infrared wavelength is selected for substantially optimumevaporation of moisture from the food product.
 39. The method of claim28, wherein the first infrared wavelength is from about 1 to about 3microns.
 40. The method of claim 28, wherein the first infraredwavelength is from about 1.96 to about 2.5 microns.
 41. The method ofclaim 28, wherein the first infrared wavelength is about 2.11 microns.42. The method of claim 28, wherein the first infrared wavelengthcomprises a first plurality of infrared wavelengths.
 43. The method ofclaim 28, wherein the second infrared wavelength comprises a secondplurality of infrared wavelengths.